CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 347,389	$ 292,341
Restricted cash	643	618
Short-term investments	202,697	193,320
Accounts receivable, net	54,887	68,154
Prepaid expenses and other current assets	15,414	10,881
Total current assets	621,030	565,314
Property and equipment, net	61,501	65,664
Capitalized software development costs, net	11,949	15,855
Deposits and other assets	6,077	2,072
Deferred tax assets, net	9,072	7,989
Total assets	709,629	656,894
Current liabilities:
Accounts payable and accrued expenses	27,524	31,840
Accrued compensation and employee benefits	40,410	40,067
Accrued restructuring costs	25	56
Deferred revenue and advance payments	121,162	100,695
Total current liabilities	189,121	172,658
Deferred revenue and advance payments	11,372	8,995
Other long-term liabilities	19,476	19,943
Deferred tax liabilities	15	17
Total liabilities	219,984	201,613
Commitments and Contingencies
Stockholders' Equity
Preferred stock undesignated, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	0	0
Additional paid-in capital	536,689	534,651
Treasury stock, at cost; 6,405 shares	(475,184)	(475,184)
Accumulated other comprehensive loss	(8,238)	(7,408)
Retained earnings	436,360	403,204
Total stockholders' equity	489,645	455,281
Total liabilities and stockholders' equity	709,629	656,894
Class A
Stockholders' Equity
Common stock	16	16
Class B Convertible
Stockholders' Equity
Common stock	$ 2	$ 2

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.